The standard for exams and longer term assignments is different. I’ve never been graded for my grammar or spelling on a law exam. I have on papers.

On an exam you could write an outline and only flesh out half of it to full sentences and still get almost full credit, sometimes even an A. You can’t do that on a written assignment.

And by the way, real practice is more like take home assignments, most of the time. You will be judged for things like your grammar and typos; even though that judgment will seldom be dispositive, if you make a habit of submitting sloppily edited documents you will one day get a hardass judge who rejects it and rules against you in default. It’s okay because you usually know about the deadlines weeks in advance so you have time to prepare and no excuse not to. But on the other hand sometimes shit happens and a deadline comes by surprise, like a reply on a filing that got lost in transit somewhere on mail service... and sometimes you can get an extension but sometimes you can’t and your half-completed outline of a memo will have to do.